1. Field of the Invention
This invention relates to a flat type optical head for focusing a light beam onto an optical memory and more particularly to a flat type optical head which is incorporated in an optical information retrieving system that uses a light beam to reproduce information from an optical memory.
2. Description of the Related Art
In the information retrieving system, an optical head is used to focus a light beam onto an optical memory. As disclosed in U.S. Pat. Nos. 4,023,033 and 4,641,023, the optical head generally comprises a light source for generating a light beam, an objective lens, which is constituted of a convex lens, for focusing the light beam emitting from the light source onto an information recording medium or optical memory and a beam splitter for directing the light beam reflected from the optical memory and coming out of the objective lens to the light detector.
As is obvious from its construction, the optical head has a limitation in miniaturization; it is difficult to reduce in size, weight and height. Due to the difficulty in miniaturization of the optical head, it is difficult to miniaturize information retrieving systems in which the optical head is used. Furthermore, due to the difficulty in reducing the weight of the optical head, the optical head moving mechanism in the information retrieving systems has to be large, thus imposing restraints on speeding up the access to information.